As a powerful diagnostic imaging apparatus for early detecting a breast cancer, conventionally, an X ray mammography apparatus is widely known. On the other hand, a method of acquiring a wide range of three-dimensional image data by using a low invasive ultrasound echo in place of X rays accompanied by an exposure is disclosed in PTL1 (Patent Literature 1) or the like, for example. The PTL1 discloses an apparatus for acquiring a three-dimensional ultrasound echo image by carrying out electronic scanning while mechanically moving an ultrasound probe (which will be hereinafter also referred to as a probe).
As a method of acquiring a three-dimensional ultrasound echo image, there is well known a method of carrying out three-dimensional electronic scanning by using a two-dimensional transducer array in which elements are arranged two-dimensionally. In order to carry out the three-dimensional electronic scanning over a wide range of imaging region with a high resolution, however, there are problems in that the number of the elements in the two-dimensional transducer array is increased, a processing scale is increased with the increase in the number of the elements, a scanning time is prolonged, and the like. For this reason, it is hard to constitute a practical ultrasound diagnostic imaging apparatus. On the other hand, since an apparatus in which mechanical scanning and electronic scanning of a probe are combined can easily pick up an image of a wide range of regions in an object, it can have a suitable structure as a three-dimensional image acquiring apparatus of an imaging region within a wide range such as an ultrasound mammography.